Young patients with a symptom complex of angina pectoris constitute a problematic group in medicine. Many of them require a detailed investigation. By combining electrophysiologic and metabolic measurements with dynamic clinical experiments, one can distinguish with great probability between normal and pathological findings. Exercise ECG, atrial pacing and simultaneous sampling of blood from artery and coronary sinus were undertaken in 57 patients aged 40 or less. Although the patients were selected according to a history of effort angina, results were normal in four and in seven other only one test was pathological. The sensitivity was highest in atrial pacing (78%) and somewhat lower in exercise ECG (75%) and lactate extraction (67%). The specificity of the tests in series was about 53%. Concordant results made a diagnosis of ischemic heart disease highly probable. Discrepancies and probably false negative results in individual cases are evident. The need for angiographic evaluation of coronary arteries and left ventricular function is clear. The stepwise advance from the usual physical examination to more demanding investigations provides a possibility of classifying the patients according to the needs of an accurate medical appraisal.